Silicone fluids as typified by dimethylpolysiloxane have improved heat resistance, low-temperature resistance, weather resistance and stable electrical properties and are used in a variety of applications including electric appliances, business machines and computer-related machines for moisutre resistant, insulating, cooling, lubricating and other purposes. At present, silicone fluids are indispensable for ensuring the reliability and function of such electric and electronic equipment.
In accordance with the demand for enhancing the function and reducing the size of such electric and electronic equipment, it is desired to reduce the contact pressure and actuating load energy of switches, relays and other elements, leaving the risk of interruption and malfunction of these elements. One of indirect causes is electric contact failures in elements such as relays, switches, motors and corotrons. It is known that electric contact failures are sometimes caused by low molecular weight siloxanes contained in silicone fluid.
To eliminate the troubles caused by low molecular weight siloxanes, there were proposed several methods including: (1) removing low molecular weight siloxanes from silicone fluid at high temperature in vacuum, (2) restricting the range of available voltage and current loading conditions (Japanese Patent Application Kokai No. 209266/1986), and (3) introducing a special organic fluorine compound having a certain vapor pressure into silicone fluid (Japanese Patent Application Kokai Nos. 104656/1989 and 109615/1989). These methods, however, have some problems. Method (1) has been used in practice, but the cost is high. Method (2) entails a lowering in the capacity of electric and electronic equipment. Method (3) is less effective in that the silicone fluid will volatilize under open service conditions and the fluorine compound added is expensive.